Getting ready to re-do most of the DC wiring in our 73 28ft express. I have at least three places where wires are grounded to the hull!!!! the aft bilge, the trim tabs ,and the fuel gauge. I know theses need to be corrected among other things. Just looking for basic suggestions to get started such as wiring size to re run the grounds to a common ground. I assume I need a ground bus bar? and please clarify....do i ground the ground bus bar to the lug on the the bulkhead or the engine? what else might i put on my shopping list as i get started?

You never know what you'll find on a dc system once you start pulling wire I see a lot of dumbfounded head shaking in your future haha!

As far as the trim tab hydraulic pump we used 10 gauge wire Check out blue sea systems for panels if you happen to need any, really well worth the money cleans up the spaghetti of wires quite well.Speaking of trim tabs the previous owner had wired them to the ignition power lead if you tried to adjust the tabs underway the port engine would just about die real exciting!